Anatomical projection of the cervical uncinate process in ventral, ventrolateral, and posterior decompressive surgery

Partial uncinatectomy combined with anterior cervical discectomy and fusion for the treatment of one-level cervical radiculopathy: analysis of clinical efficacy and sagittal alignment

BACKGROUND

Biomechanical studies have demonstrated that uncovertebral joint contributes to segment mobility and stability to a certain extent. Simultaneously, osteophytes arising from the uncinate process are a common cause of cervical spondylotic radiculopathy (CSR). For such patients, partial uncinatectomy (UT) may be required. However, the clinical efficacy and sagittal alignment of partial UT during anterior cervical discectomy and fusion (ACDF) have not been fully elucidated.

METHODS

A total of 87 patients who had undergone single level ACDF using a zero-profile device from July 2014 to December 2018 were included. Based on whether the foraminal part of the uncovertebral joint was resected or preserved, the patients were divided into the ACDF with UT group (n = 37) and the ACDF without UT group (n = 50). Perioperative data, radiographic parameters, clinical outcomes, and complications were compared between the two groups.

RESULTS

The mean follow-up was 16.86 ± 5.63 and 18.36 ± 7.51 months in the ACDF with UT group and ACDF without UT group, respectively (p > 0.05). The average preoperative VAS arm score was 5.89 ± 1.00 in the ACDF with UT group and 5.18 ± 1.21 in the ACDF without UT group (p = 0.038). However, the average VAS arm score was 4.22 ± 0.64, 4.06 ± 1.13 and 1.68 ± 0.71, 1.60 ± 0.70 at 1 week post operation and at final follow up, respectively, (p > 0.05). We also found that the C2-7 SVA and St-SVA at the last follow-up and their change (last follow-up value - preoperative value) in the ACDF with UT group were significantly higher than ACDF without UT group (p < 0.05). No marked differences in the other cervical sagittal parameters, fusion rate or complications, including dysphagia, ASD, and subsidence, were observed.

CONCLUSIONS

Our result indicates that ACDF using a zero-p implant with or without partial UT both provide satisfactory clinical efficacy and acceptable safety. However, additional partial UT may has a negative effect on cervical sagittal alignment.

Vertebral Artery Mobilization and Cervical Tumor Resection

BACKGROUND

To emphasize the importance of vertebral artery (VA) mobilization by reviewing the anatomy and variations of the VA while performing total resection of VA-associated tumors that develop from different tissues.

METHODS

VA mobilization and mass resection were performed after the evaluation and preoperative imaging of 22 patients with VA-related tumors. Anterior, posterior, or both approaches were conducted on the patients and stabilization was also applied to the patients in need. Radiotherapy and/or chemotherapy were planned for patients with malignant tumors as shown by histopathology.

RESULTS

Overall, 17 patients with benign and 5 patients with malignant tumors underwent tumor resection with VA mobilizing. There were 13 male and 9 female patients with a mean age of 29.3 years. The average follow-up duration was 53 months. All the patients received gross total tumor resection and had a good postoperative neurological recovery. No complications were observed; local recurrence was observed only in 2 patients.

CONCLUSIONS

VA mobilization reduces the need for instrumentation in VA-related cases, especially nerve tumors, and increases the possibility of the surgical resection of vertebral tumors.

Microanatomical considerations for safe uncinate removal during anterior cervical discectomy and fusion: 10-year experience

Cervical radiculopathy from uncovertebral joint (UVJ) hypertrophy and nerve root compression often occurs anterior and lateral within the cervical intervertebral foramen, presenting a challenge for complete decompression through anterior cervical approaches owing to the intimate association with the vertebral artery and associated venous plexus. Complete uncinatectomy during anterior cervical discectomy and fusion (ACDF) is a controversial topic, many surgeons relying on indirect nerve root decompression from restoration of disc space height. However, in cases of severe UVJ hypertrophy, indirect decompression does not adequately address the underlying pathophysiology of anterolateral foraminal stenosis. Previous reports in the literature have described techniques involving extensive dissection of the cervical transverse process and lateral uncinate process (UP) in order to identify the vertebral artery for safe removal of the UP. Recent anatomical investigations have detailed the microanatomical organization of the fibroligamentous complex surrounding the UP and neurovascular structures. The use of the natural planes formed from the encapsulation of these connective tissue layers provides a safe passage for lateral UP dissection during anterior cervical approaches. This can be performed from within the disc space during ACDF to avoid extensive lateral dissection. In this article, we present our 10-year experience using an anatomy-based microsurgical technique for safe and complete removal of the UP during ACDF for cervical radiculopathy caused by UVJ hypertrophy.

Total Anterior Uncinatectomy During Anterior Discectomy and Fusion for Recurrent Cervical Radiculopathy: A Two-dimensional Operative Video and Technical Report

A common cause of cervical radiculopathy from degenerative foraminal stenosis is severe uncovertebral hypertrophy. It is difficult to accomplish complete foraminal decompression in these cases with posterior techniques without the removal of a large portion of the facet joint. Total removal of the uncovertebral joint from an anterior approach allows for complete decompression of the exiting cervical nerve root and has been shown to be a safe technique. In this surgical video and technical report, we demonstrate the surgical anatomy and operative technique of a two-level anterior uncinatectomy during anterior discectomy and fusion (ACDF) for recurrent cervical radiculopathy after a previous multi-level posterior foraminotomy. The patient is a 67-year-old male with a progressive left arm and neck pain with radiographic, clinical, and electrophysiologic diagnostic evidence of active C6 and C7 radiculopathies from degenerative foraminal stenosis at the C5-6 and C6-7 levels. Posterior foraminotomies had been performed without significant improvement in his radicular pain. A repeat MRI demonstrated lateral foraminal stenosis from severe uncovertebral joint hypertrophy at the C5-6 and C6-7 levels. After acquiring informed consent from the patient, an anterior approach was performed with complete removal of the uncovertebral joints at both levels with discectomy and fusion. Postoperatively, the patient had complete resolution of his radicular pain and remained pain-free at the latest follow-up. Complete uncinatectomy and ACDF is an effective technique for complete foraminal decompression in cases of refractory radiculopathy and neck pain after unsuccessful posterior decompression.

Risk assessment of vertebral artery injury in anterior controllable antedisplacement and fusion (ACAF) surgery: a cadaveric and radiologic study

PURPOSE

We have introduced a novel surgery technique named anterior controllable antedisplacement and fusion (ACAF) for the treatment of ossification of the posterior longitudinal ligament. As reported, the satisfactory postoperative outcome can be attributed to the larger decompression width. However, it may associate with high prevalence of vertebral artery injury (VAI) theoretically. Thus, assessment of the vulnerability of vertebral artery in ACAF is of great importance.

METHODS

Computed tomographic scan data of 28 patients were retrospectively studied. Seven radiographic parameters were evaluated: uncinate process (UP) tips distance, transverse foramen (TF)-UP tips distance, TF-LWL (the ipsilateral limited wedging line) distance, the limited distance of lateral decompression, the maximum oblique angle of LWL, TF-LWG (the lateral wall of groove) distance, and width of groove. Eleven fresh cadaveric spines undergoing ACAF surgery were also studied. Two anatomic parameters were evaluated: width of groove and LWG-TF distance.

RESULTS

The UP tips distance increased from C3 to C6 and tended to be larger in males. The UP tip-TF distance and LWL-TF distance were smallest at C4, but both were larger than 2 mm. Maximum oblique angle decreased from C3 to C6. Postoperatively, both radiographic and cadaveric measurements showed the width of groove was larger than UP tips distance, but LWG-TF distance was larger than 2 mm in all levels.

CONCLUSION

UP can be used as anatomical landmarks to avoid VAI during ACAF surgery. Radiographic and cadaveric measurements verified the safety of ACAF surgery, even for those cases with wedging and lateral slotting.

Morphometry of the Uncinate Process, Vertebral Body, and Lamina of the C3-7 Vertebrae Relevant to Cervical Spine Surgery

Objective

The cervical spine consists of 4 typical and 3 atypical vertebrae. The uncinate process is one of the unique features of the cervical vertebrae. Uncinectomy and uncoforaminotomy are widely used to decompress the nerve in the intervertebral foramen and to remove osteophytes from the uncinate process. Morphometric analyses of the uncinate process help spine surgeons obtain a 3-dimensional orientation for approaching the cervical spine with minimal risk to the surrounding vascular and neural structures. This study aims to analyze the morphometry of uncinate process of cervical vertebrae with relevant to cervical spine surgery.

Methods

Eighty dry adult cervical vertebrae were studied, and 11 parameters were measured. Seven parameters were paired and 4 were unpaired.

Results

The height of the uncinate process progressively increased from C3 to C6 and decreased at C7. The length of the uncinate process increased from C3 to C6–7. The width was greatest at C6 and smallest at C3. The vertebral body width and anteroposterior diameter gradually increased from C3 to C7. The parameters of the lamina also increased from C3 to C7.

Conclusion

Precise knowledge about the cervical vertebrae is useful for diagnosing both common and uncommon causes of symptoms and for choosing an appropriate approach. Thus, it helps to increase the success rate of cervical surgery.

Study of the Transverse Foramen in the Subaxial Cervical Spine in Korean Patients With Degenerative Changes: An Anatomical Note

Background/Aims

The purpose of this study was to provide anatomical data on the dimensions and location of the subaxial transverse foramen (TF) in relation to surgical landmarks routinely used during anterior cervical procedures.

Methods

A total of 116 patients who underwent preoperative computed tomography (CT) evaluations for degenerative cervical disease were enrolled. Axial and coronal CT images of the cervical vertebrae from C3 to C6 were analyzed to measure interforaminal distance, the TF distance from the anterior and posterior vertebral body margin, TF dimensions, and the TF medial margin from the tip and medial margin of the uncus. Comparative and correlative analyses were also performed according to age, body mass index (BMI), and sex.

Results

All measurement values in male patients were larger than those in their female counterparts. The interforaminal distance gradually increased from C3 to C6. The distance of the TF medial margin from the tip of the uncus was found be above approximately 3 mm in all vertebrae except C6. Correlation analysis revealed that age had a significant negative relationship with the transverse diameter of TF. In contrast, BMI had a significant positive correlation with interforaminal distance. Moreover, the distances of the TF medial margin from the tip and medial margin of the uncus showed strong negative correlations with age.

Conclusion

Useful morphometric data were obtained that may help the operating surgeon to avoid vertebral artery injury. The safe distance from the tip of the uncus to the TF medial margin was found to be approximately 3 mm, and this distance should not be violated during lateral decompression. In addition, this value may decrease with age.

Surgical Anatomy of the Longus Colli Muscle and Uncinate Process in the Cervical Spine

PURPOSE

There have been a few previous reports regarding the distances between the medial borders of the longus colli to expose the disc space. However, to our knowledge, there are no reports concerning longus colli dissection to expose the uncinate processes. This study was undertaken to assess the surgical relationship between the longus colli muscle and the uncinate process in the cervical spine.

MATERIALS AND METHODS

This study included 120 Korean patients randomly selected from 333 who had cervical spine MRIs and CTs from January 2003 to October 2013. They consisted of 60 males and 60 females. Each group was subdivided into six groups by age from 20 to 70 years or more. We measured three parameters on MRIs from C3 to T1: left and right longus colli distance and inter-longus colli distance. We also measured three parameters on CT: left and right uncinate distance and inter-uncinate distance.

RESULTS

The longus colli distances, uncinate distances, and inter-uncinate distances increased from C3 to T1. The inter-longus colli distances increased from C3 to C7. There was no difference in longus colli distances and uncinate distances between males and females. There was no difference in the six parameters for the different age groups.

CONCLUSION

Although approximate guidelines, we recommend the longus colli be dissected approximately 5 mm at C3-5, 6 mm at C5-6, 7 mm at C6-7, and 8 mm at C7-T1 to expose the uncinate process to its lateral edge.

Musculoskeletal Ultrasound: A Novel Approach for Luschka's Joint and Vertebral Artery

Background

Cervical vertigo has been a controversial diagnosis for several years, and the lack of a diagnostic test is a critical problem. Musculoskeletal ultrasound (MSUS) is a real-time dynamic approach that is used to investigate the musculoskeletal and vascular systems.

Material/Methods

In this study, MSUS was used to examine whether there is a relationship among vertigo, the vertebral artery (VA), and Luschka’s joint proliferation in patients with cervical vertigo.

Results

MSUS clearly revealed the size, shape, and characteristics of the Luschka’s joint, the VA, and the surrounding structures. The Luschka’s joint proliferation was not distributed uniformly, but the predilection sites were C4/5 (50.5%) and C5/6 (32.3%). The proliferation from C4/5 and C5/6 Luschka’s joints was the major cause of the grade 2/3 VA tortuosity. Moreover, there was a significant correlation between VA compression from Luschka’s joint proliferation and the symptoms of cervical vertigo.

Conclusions

MSUS is a real-time and noninvasive technique that can be used to locate and observe Luschka’s joint and the VA during research and clinical applications. In future practice MSUS could be used as a diagnostic approach for patients with suspected cervical vertigo.

Morphometric evaluation of the uncinate process and its importance in surgical approaches to the cervical spine: a cadaveric study

INTRODUCTION

The uncinate process (UP) has an important role because of its relationship with the vertebral artery and spinal roots. Degenerative diseases cause osteophyte formation on the UP, leading to radiculopathy, myelopathy and vertebral vascular insufficiency, which may require surgical management. This study aimed to evaluate the morphometry of this region to shed light on the anatomy of the UP.

METHODS

Morphometric data was obtained from 13 male formaldehyde-fixed cadavers. Direct measurements were obtained using a metal caliper. Computed tomography (CT) morphometry was performed with the cadavers in the supine position.

RESULTS

Direct cadaveric measurements showed that the height of the UP increased from C3 (5.8 ± 1.0 mm) to C7 (6.6 ± 0.5 mm). On CT, the corresponding measurements were 5.9 ± 1.2 mm at C3 and 6.9 ± 0.6 mm at C7. The distance between the left and right apex of the UP from C3 to C7 also increased on both direct cadaveric and CT measurements (C3: 20.8 ± 1.0 mm and C7: 28.1 ± 2.4 mm vs. C3: 23.7 ± 3.4 mm and C7: 29.0 ± 3.0 mm, respectively). On CT, the distance between the UP and superior articular process at the C3 to C7 levels were 9.8 ± 1.7 mm, 7.9 ± 1.8 mm, 7.9 ± 1.6 mm, 7.8 ± 1.3 mm and 8.2 ± 1.7 mm, respectively.

CONCLUSION

Direct cadaveric and CT measurements of the UP are useful for preoperative evaluation of the cervical spine and may lead to better surgical outcomes.

Surgical Anatomy of the Uncinate Process and Transverse Foramen Determined by Computed Tomography

Study Design Computed tomography-based cohort study. Objective Although there are publications concerning the relationship between the vertebral artery and uncinate process, there is no practical guide detailing the dimensions of this region to use during decompression of the intervertebral foramen. The purpose of this study is to determine the anatomic parameters that can be used as a guide for thorough decompression of the intervertebral foramen. Methods Fifty-one patients with three-dimensional computed tomography scans of the cervical spine from 2003 to 2012 were included. On axial views, we measured the distance from the midline to the medial and lateral cortices of the pedicle bilaterally from C3 to C7. On coronal reconstructed views, we measured the minimum height of the uncinate process from the cranial cortex of the pedicle adjacent to the posterior cortex of vertebral body and the maximal height of the uncinate process from the cranial cortex of the pedicle at the midportion of the vertebral body bilaterally from C3 to C7. Results The mean distances from midline to the medial and lateral cortices of the pedicle were 10.1 ± 1.3 mm and 13.9 ± 1.5 mm, respectively. The mean minimum height of the uncinate process from the cranial cortex of the pedicle was 4.6 ± 1.6 mm and the mean maximal height was 6.1 ± 1.7 mm. Conclusions Our results suggest that in most cases, one can thoroughly decompress the intervertebral foramen by removing the uncinate out to 13 mm laterally from the midline and 4 mm above the pedicle without violating the transverse foramen.

Virtual pathology of cervical radiculopathy based on 3D MR/CT fusion images: impingement, flattening or twisted condition of the compressed nerve root in three cases

Background

There have been several imaging studies of cervical radiculopathy, but no three-dimensional (3D) images have shown the path, position, and pathological changes of the cervical nerve roots and spinal root ganglion relative to the cervical bony structure. The objective of this study was to introduce a technique that enables the virtual pathology of the nerve root to be assessed using 3D magnetic resonance (MR)/computed tomography (CT) fusion images that show the compression of the proximal portion of the cervical nerve root by both the herniated disc and the preforaminal or foraminal bony spur in patients with cervical radiculopathy.

Findings

MR and CT images were obtained from three patients with cervical radiculopathy. 3D MR images were placed onto 3D CT images using a computer workstation.

The entire nerve root could be visualized in 3D with or without the vertebrae. The most important characteristic evident on the images was flattening of the nerve root by a bony spur. The affected root was constricted at a pre-ganglion site. In cases of severe deformity, the flattened portion of the root seemed to change the angle of its path, resulting in twisted condition.

Conclusions

The 3D MR/CT fusion imaging technique enhances visualization of pathoanatomy in cervical hidden area that is composed of the root and intervertebral foramen. This technique provides two distinct advantages for diagnosis of cervical radiculopathy. First, the isolation of individual vertebra clarifies the deformities of the whole root groove, including both the uncinate process and superior articular process in the cervical spine. Second, the tortuous or twisted condition of a compressed root can be visualized.

The surgeon can identify the narrowest face of the root if they view the MR/CT fusion image from the posterolateral-inferior direction. Surgeons use MR/CT fusion images as a pre-operative map and for intraoperative navigation. The MR/CT fusion images can also be used as educational materials for all hospital staff and for patients and patients’ families who provide informed consent for treatments.

Morphometrical study of uncinate processes and vertebral body of cervical spine

OBJECTIVE

The anatomical knowledge is the most important and has a direct link with success of operation in cervical spine surgery. The authors measured various cervical parameters in cadaveric dry bones and compared with previous reported results.

METHODS

We made 255 dry bones age from 19 to 72 years (mean, 42.3 years) that were obtained from 51 subjects in 100 subjects who donated their bodies. All measurements from C3-C7 levels were made using digital vernier calipers, standard goniometer, and self-made fix tool for two different cervical axes (canal and disc setting). We classified into 4 groups (uncinate process, vertebral body, lamina, and pedicle) and measured independently by two neurosurgeons for 28 parameters.

RESULTS

We analyzed 23970 measurements by mean value and standard deviations. In comparing with previous literatures, there are some different results. The mean values for uncinate process (UP) width ranged from 5.5 mm at C4 and 5 to 6.3 mm at C3 and C7 in men. Also, in women, the mean values for UP width ranged from 5.5 mm at C5 to 6.3 mm at C7. C7 was widest and C5 was most narrow than other levels. The antero-posterior length of UP tended to increase gradually from C3 to C6. The tip way, tip distance, and base distance of UP also showed increasing pattern from C3 to C7.

CONCLUSION

These measurements can provide the spinal surgeons with a starting point to address bony architectures surrounding targeted soft tissues for safeguard against unintended damages during cervical operation.

Clinical importance of ligamentous and osseous structures in the cervical uncovertebral foraminal region

The vertebral artery, cervical spinal nerves, spinal nerve roots, and the bony and ligamentous tissue related to the cervical vertebrae are structures whose anatomy determines the path of a surgical approach. Defining the anatomy and, in particular, determining the precise location of vulnerable structures at the intervertebral foramen and the uncovertebral foraminal region (UVFR), a region defined by the uncinate process anteriorly, the facet joint posteriorly and the foramen transversarium laterally, has critical significance when selecting the safest surgical approach. We studied the anatomy of the vertebral artery, cervical spinal nerves, and spinal nerve roots within the UVFR in six cadaver specimens. We also obtained measurements of bony structures in 35 dry cervical vertebral columns, from C3-C7. The uncinate process (UP) projects superiorly from the posterolateral aspect of each cervical vertebral body, except for the first and second vertebrae. Because the posterior part of the UP lies adjacent to the vertebral artery, spinal nerve, and spinal nerve roots, its resection creates sufficient space to decompress these structures directly. The posterolateral surface of the UP is covered by ligamentous tissue that originates from the posterior longitudinal ligament and protects the neural and vascular structures during their decompression in the UVFR.